Development of fennel essential oil-loaded Zein electrospun fibers for antimicrobial and postharvest preservation of tangerines

Abstract

Recent advances in postharvest technology have been driven by the development of electrospun fibers from biodegradable, edible polymers. In this study, we aimed to create zein-based electrospun fibers incorporating fennel essential oil (FEO) at varying concentrations of 0, 5, 10, and 20% (w/v) to prolong the shelf life of tangerines during storage. SEM analysis revealed that the average fiber diameter increased from 311 nm to 748 nm with the addition of FEO. FTIR spectroscopy indicated hydrophobic interactions between zein and FEO, while X-ray diffraction analysis showed that increasing FEO concentrations up to 20% intensified the diffraction peaks. Differential scanning calorimetry revealed that the glass transition temperature (Tg) of the zein fibers decreased from 161.2 ºC to 137.2 ºC with FEO addition. BET analysis demonstrated that the fibers were mesoporous, with pore sizes ranging from 8 nm to 10 nm. Antimicrobial tests using disc diffusion showed that FEO-loaded fibers effectively inhibited the growth of both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, with inhibition zone diameters measuring 22 mm and 15 mm, respectively. Zein electrospun mats were directly applied to the tangerines, allowing the mats to adhere to the surface and achieve a complete, uniform coating. The FEO-loaded zein mats positively impacted the quality of tangerines, improving firmness, TSS, titratable acidity (TA), and weight during 28 days of storage. These findings highlight the potential of FEO-loaded zein electrospun fibers for enhancing the postharvest storage of tangerines, reinforcing the benefits of biodegradable, edible fibers in preserving non-climacteric fruits.

Graphical Abstract